User Manual

Configure Switching Information
269
M4200 and M4300 Series ProSAFE Managed Switches Web Management User Manual
The following table describes the nonconfigurable data that the MVRP Global Statistics page
displays.
Loop Protection
Loop protection can detect physical and logical loops between Ethernet ports on a device.
About Loop Protection
Loops inside a network are costly because they consume resources and reduce the
performance of the network. Detecting loops manually can be cumbersome.
The switch can automatically identify loops in the network. You can enable loop protection
per port or globally.
If loop protection is enabled, the switch sends predefined protocol data unit (PDU) packets to
a Layer 2 multicast destination address (09:00:09:09:13:A6) on all ports for which the feature
is enabled. You can selectively disable PDU packet transmission for loop protection on
specific ports even while port loop protection is enabled. If the switch receives a packet with
the previously mentioned multicast destination address, the source MAC address in the
packet is compared with the MAC address of the switch. If the MAC address does not match,
the packet is forwarded to all ports that are members of the same VLAN, just like any other
multicast packet. The packet is not forwarded to the port from which it was received.
Table 101. MVRP Statistics
Field Description
Interface In the MVRP Statistics table, this field identifies the interface associated with
the rest of the data in the row.
Frames Received The number of MVRP frames that were received on the switch.
Bad Header The number of MVRP frames with bad headers that were received on the
switch.
Bad Format The number of MVRP frames with bad PDUs body formats that were received
on the switch.
Frames Transmitted The number of MVRP frames that were transmitted on the switch.
Transmission Failures The number of MVRP frames that the switch failed to transmit.
Message Queue Failures The number of messages that failed to be added to the queue.
Registration Failures The number of MVRP frames that failed to register on a device or particular
interface.